Executing single file csharp files.

Have you ever wondered if .cs files can be executed without .csproj file, we can absolutely execute them with dotnet run command. This a new feature from .NET 10 (C#14)

• Create a simple .cs file and save it. (eg: hello.cs)

       Console.WriteLine("Hello world");

• Execute the file using dotnet run ./hello.cs

• No imports necessary as by default this single file execution imports most used libraries.

• The build files are stored in a temp folder.

• This also has unix shebang (#!) support.

       #!dotnet run
       Console.WriteLine("Hello world");

• Adjust the permissions

       chmod +x hello.cs

• Execute the program with ./hello.cs

• If you also do not want the .cs extension, you can rename the filename mv hello.cs hello and it still works.

Reading command line arguments.

• Add the following contents to the .cs file.

    if (args.length > 0)
    {
      string message = string.Join(' ', args);
      Console.WriteLine(message)
    }

• You can pass the arguments as follows.

    ./hello -- This is a command line.

The -- option indicates the all following arguments to be passed to the program.

Import nuget packages

• Add this line after the unix shebang line to import the nuget package.

   #:package System.CommandLine@2.0.0

For more info

File-Based-Programs